During the last decade, ADCs using single ramp architecture have been
widely used in integrated circuits dedicated to nuclear science
applications. These types of converters are actually very well suited for
low power, multi-channel applications. Moreover their wide dynamic range
and their very good differential non-linearity are perfectly matched to
spectroscopy measurement. Unfortunately, their use is limited by their long
conversion time, itself limited by their maximum clock frequency. A new
architecture is described in this paper. It permits speeding up the
conversion time of the traditional ramp ADC structures by a factor of 32
while keeping a low power consumption. Measurement results on a 4-channel,
12-bit prototype using a 3.2 GHz virtual clock are then presented in
detail, showing excellent performances of linearity and noise.
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